Raglan sleeves

How to join raglan sleeves to the front and back of knitted pieces.
I have blocked all pieces to the measurements given in the pattern and want to make sure I join them all correctly.
Thank you.

Usually mattress stitch works for these seams and looks best.

from sewing experience I would say:

find the joining points (depending on your cut) and mark them. then line up the piece.

close the sleeve and the side seam of the piece last.

I would use mattress stitch as well.